(CNN) — A federal grand jury has indicted 13 Russian nationals and three Russian entities for allegedly meddling in the 2016 presidential election, charging them with conspiracy to defraud the United States, the Department of Justice announced Friday.

In addition, three defendants were charged with conspiracy to commit wire fraud and bank fraud, and five defendants with aggravated identity theft.

“The defendants allegedly conducted what they called information warfare against the United States, with the stated goal of spreading distrust towards the candidates and the political system in general,” Deputy Attorney General Rod Rosenstein said.

The grand jury had been empaneled by special counsel Robert Mueller, who is investigating Russian interference in the 2016 election as well as any possible connections between Russia and Trump campaign associates.

FBI Director Chris Wray and Rosenstein briefed President Donald Trump on the indictments at the White House on Friday morning, a White House official said.

Beginning as early as 2014, the Russian organization Internet Research Agency began operations to interfere with the US political system, including the 2016 elections, according to the indictment.

The defendants allegedly posed as US persons, created false US personas, and operated social media pages and groups designed to attract US audiences, the indictment reads.

The Internet Research Agency had a “strategic goal to sow discord in the US political system” including the election, according to the indictment.

Russians posted “derogatory information about a number of candidates,” and by mid-2016 they supported Trump and disparaged Democratic candidate Hillary Clinton. They bought ads and communicated with “unwitting” people tied to Trump campaign and others to coordinate political activities.

Rosenstein said Friday that the indictment does not contain any allegations that any Americans knowingly participated in the activity.

“There is no allegation in this indictment that any American was a knowing participant in this illegal activity,” he said. “There is no allegation in the indictment that the charge conduct altered the outcome of the 2016 election.”